The present invention relates to a cap for an end of a hollow post.
In viticulture it is common to train vines to grow along wires suspended between posts. In recent times, it has become usual for such posts to be formed of metal. Many such posts are formed by rolling or pressing lengths of metal sheet to form a multi-sided post, the post being hollow in the sense that it surrounds a hollow area. The posts are driven into the ground and wires are threaded through holes or cut-outs in the posts to form a trellis of wires. Vine plants are planted at the base of these wires and, as they grow, are trained to grow along the wires. Sometimes, netting is placed over the mature vines in order to make it harder for birds to eat the grapes. One problem with this technique is that the netting can easily snag on the top of the metal posts when it is being removed, hence damaging the netting. For this reason, post caps have been developed which are fitted to the top of the posts. The netting rests on the post cap, thereby preventing the netting from catching on the post.
The problem with caps currently on the market is that they do not fit tightly enough to the posts to prevent the caps from being pulled off by the nets when the nets are removed. Removal of the nets is done mechanically by a specially designed machine which is driven between two rows of vines to lift the net off the vines to allow the grapes to be harvested. The mechanical nature of the removal makes it difficult for it to be delicate enough to avoid removing the caps. The removal of the caps means that they must be gathered manually, hence increasing the labour component involved in removing the netting. Further, it will be appreciated that caps may be caught up in the netting and require removal and also that caps can be lost or damaged and require replacing.
Further, a number of different post designs are now on the market. Many such posts are formed of sheet metal cut to standard lengths and then rolled or bent to form a post which enclose a hollow such that the transverse cross-section of the post provides rigidity in the post and resists its deformation. Such posts may be open at one side or rolled so that there is only a small gap between the two free edges of the sheet. It is possible that a vine yard would employ a number of different styles of such postsxe2x80x94even for a single row of vines. A disadvantage of current post caps is that they do not fit more than one hollow post.
It is an object of the present invention to overcome one or more of the foregoing problems by providing an alternative post cap.
Accordingly the invention provides a cap for an end of a hollow post, said cap having a generally domed head which, in use, overlies a radially outermost portion of the end of the post, and under said domed head a stem for inserting within the hollow post,
said stem having at least one radially outwardly extending abutment means extending along the length of said stem for engaging with an inner wall of the post when said stem is inserted in end of the post,
said abutment means serving to provide an interference fit of the stem in the end of said post such that to insert said stem substantially all the way into the end of said post requires force fitting and either deformation or shearing of material from said abutment means.
Preferably, the cap is for an end of a post that has a transverse cross-sectional shape with multiple inner corners and where said abutment means includes at least two single wall flanges extending along the length of the stem, one flange being for engaging with one of said inner corners and the other flange being for engaging with another of said inner corners.
Preferably, said abutment means includes at least four flanges said flanges being arranged in pairs on opposite sides of said stem, the flanges of a pair being spaced apart from each other whereby each pair of flanges may engage a pair of inner corners of said posts.
Preferably, where said post has an opening extending along its length defined by two inturned lips of the posts, the inturned lips abut against one of the pairs of spaced flanges.
Preferably, said inturned lips engage with the sides of said flanges.
Preferably, said stem is hollow.
Preferably, the transverse cross-section of said stem has the shape of a flattened oval, the flattened portions being sides of said stem and the rounded portions being ends.
Preferably, said at least four flanges are located in two pairs on respective sides of said stem.
Preferably, said abutment means includes at least one flange on either end of the stem said flange is extending radially at an angle of approximately 90xc2x0 to said side flanges.
Preferably, said stem has a slot in each side to enable a wire to pass through said stem.
Preferably, the head is hollow and has radially extending head flanges formed on the undersurface of the dome, said head flanges having a slot therein to receive the thickness of the material of the end of the post when the cap is fitted as far as possible over the end of the post.
Preferably, said head flanges have slots at different radial distances to fit said cap to post having different transverse cross-sectional profiles
Preferably, said abutment means is spaced and sized to enable fitting of said cap to posts that have different transverse cross-sectional profiles so one of said caps can be fitted to one or other of the posts depending on which post is chosen.